fix(rules): minimum damage - a landed hit reduced below 1 by DR/energy resistance deals 1 (CRB Damage - Minimum Damage, nonlethal approximated as normal)

src/pf1e_simulator/combat.py

@@ -180,6 +180,7 @@ _CHARGE_AC_PENALTY = 2  # PF1e: -2 AC until start of next turn after charging
 _CHARGE_MIN_CELLS = 2  # PF1e: charge must move at least 10 ft (2 squares)
 _UP_CLOSE_RANGE_FT = 30  # PF1e: Up Close and Deadly works within 30 ft
 _GRAPPLED_CMB_PENALTY = 2  # PF1e: grappled/pinned -2 on non-grapple/escape CMB
+_MINIMUM_HIT_DAMAGE = 1  # PF1e (CRB "Damage" - Minimum Damage): a hit deals >= 1
 _DISARM_RETALIATION_MARGIN = 10  # PF1e SRD: disarm fails by 10 -> attacker drops
 # PF1e: Point-Blank Shot grants +1/+1 within 30 ft with ranged weapons
 _POINT_BLANK_RANGE_FT = 30
@@ -2981,9 +2982,15 @@ class CombatEngine:
         )
         physical = max(0, damage - energy_share)
         damage = self._apply_dr(physical, weapon, target) + energy_share
-        return crit, False, self._apply_energy_resistance_per_component(
+        final = self._apply_energy_resistance_per_component(
             damage, weapon, rolls, target=target
         )
+        # PF1e (CRB "Damage" — Minimum Damage): "If penalties reduce the
+        # damage result to less than 1, a hit still deals 1 point of
+        # nonlethal damage." The engine has no nonlethal damage track
+        # (documented approximation): the floor is applied as 1 point of
+        # normal damage on a landed hit.
+        return crit, False, max(_MINIMUM_HIT_DAMAGE, final)
 
     def _attack_cover_bonus(
         self, attacker: CombatantState, target: CombatantState, *, ranged: bool